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Our goal was to determine whether transforming growth factor b (TGFb) isoforms were involved in the process of sperm survivability in the sperm-storage tubules (SST) in the utero-vaginal junction (UVJ) of hen oviduct. The birds were artificially inseminated. The mRNA expressions of three types of TGFb isoforms (TGFb2, TGFb3, and TGFb4) and three types of receptors (TbR1, TbR2, and TbR3) were examined in the presence or in the absence of resident sperm in SST by semi-quantitative reverse transcriptase-PCR. The mRNA expression of TGFbs and TbRs in sperm was also examined. Immunocytochemistry and western blot were performed for TbR2 to confirm its localization in UVJ. The sperm were observed at least 10 days after insemination by histology. The mRNA expressions of TGFbs and TbRs were significantly increased in UVJ in the presence of resident sperm in SST. The mRNA expressions of TGFbs and TbRs were also observed in sperm. Immunohistochemistry revealed that TbR2 were located in lymphocytes in UVJ and SST cells. The presence of TbR2 in UVJ was also confirmed by western blot. These results suggest that enhanced expressions of TGFbs and TbRs in UVJ may protect sperm in SST, probably by suppressing anti-sperm immunoreactions.

A unique property of the avian oviduct is to store sperm for a prolonged period. The sperm storage tubules (SST) are located in the utero‐vaginal junction of the oviduct, where sperm can be stored and survived for a few weeks after insemination or natural mating. The immune system in the oviduct is essential to prevent tissue infection by various microorganisms, and it may also affect the fate and survivability of sperm in the oviduct. Anti‐sperm immunoresponses including infiltration of leukocytes may be induced in the vagina of the oviduct. Sperm that will participate in fertilization may be selected by these immunoresponses. However, sperm stored in the SST may be protected from the immunoresponse by SST structures and transforming growth factor β, whose expression is increased during sperm storage in the SST. In this review, the mechanism of sperm survivability with reference to the regulation of anti‐sperm immunoresponses in hen oviduct is emphasized.

The aim of this study was to determine the physiological significance of interleukin-1b (IL1B) and lipopolysaccharide-induced TNF factor (LITAF) in the fate of sperm in the oviduct of laying hens after artificial insemination (AI ). Laying hens were inseminated with fresh semen, PBS or seminal plasma and tissues from different oviductal segments were collected to observe the general histology, changes in the mRNA expression of IL1B and LITAF and the localization of positive cells expressing immunoreactive IL1B (irIL1B). Semi-quantitative RT-PCR was used to observe the changes in mRNA expression of these molecules in the infundibulum, uterus, utero-vaginal junction (UVJ), and vagina after insemination. Intact sperm in the lumen and between the primary or secondary folds of the vagina were found until 6 h after insemination but were degraded at 12 h. The mRNA expression of IL1B and LITAF was significantly increased in the vagina until 6 h after AI but remained unchanged in the other oviductal segments. In the tissue of the vagina and UVJ, irIL1B was localized in the mucosal stroma. The number of irIL1B-positive cells was increased in the vagina but almost unchanged in UVJ after insemination with semen. Significant changes were not observed in the mRNA expression and irIL1B-positive cells in the vagina after PBS or seminal plasma insemination. The increase of IL1B and LITAF in the vagina may lead to sperm degradation and elimination by cilia of surface epithelium, whereas their lower levels in UVJ may permit sperm to survive in sperm storage tubules.

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